Images

Place logos, diagrams and generated charts on a sheet

Images anchor to a rectangle of cells. Give a path or raw bytes, plus the corners.

jet.write_sheet_arrow(
    df.to_arrow(),
    "report.xlsx",
    images=[{
        "path": "company_logo.png",
        "from_col": 0, "from_row": 0,
        "to_col": 2,   "to_row": 4,
    }],
)

Image coordinates are 0-based on both axes, unlike cell styles and tables where rows are 1-based.

From a file

path · str · required

Path to the image on disk.

from_col · int · required

0-based left column.

from_row · int · required

0-based top row.

to_col · int · required

0-based right column.

to_row · int · required

0-based bottom row.

From bytes

Use this when the image never touches disk, whether downloaded, read from a database, or generated in the same script.

data · bytes · required

Raw image bytes.

extension · str · required

Format, such as "png". Required, since there’s no filename to infer from.

import matplotlib.pyplot as plt
import io

fig, ax = plt.subplots()
ax.plot([1, 2, 3, 4], [10, 20, 15, 25])

buffer = io.BytesIO()
fig.savefig(buffer, format="png", dpi=150, bbox_inches="tight")
plt.close(fig)

jet.write_sheet_arrow(
    df.to_arrow(),
    "report.xlsx",
    images=[{
        "data": buffer.getvalue(),
        "extension": "png",
        "from_col": 5, "from_row": 1,
        "to_col": 15,  "to_row": 20,
    }],
)

This is the practical route to chart types Jetxl doesn’t offer natively. Render it with matplotlib or plotly and embed the PNG. The trade-off is that the result is a picture, so it won’t update when the underlying cells change the way a native chart does.

Formats

Format	Extensions	Best for
PNG	.png	Logos and screenshots. Lossless, supports transparency
JPEG	.jpg, .jpeg	Photographs. Smaller, no transparency
GIF	.gif	Simple graphics, limited palette
BMP	.bmp	Uncompressed Windows bitmaps
TIFF	.tiff, .tif	Print-quality source images

Sizing

The rectangle you give determines the displayed size, so aspect ratio is yours to manage. A wide anchor around a square logo stretches it.

Logos and icons

Roughly 2 to 4 columns by 5 to 8 rows.

Photographs

Roughly 4 to 6 columns by 8 to 12 rows.

Charts and diagrams

Roughly 6 to 10 columns by 12 to 20 rows.

Jetxl embeds images whole. A handful of multi-megabyte photographs produces a workbook that’s slow to open and awkward to email, so resize before embedding.